1. Field of Invention
This invention relates to systems and methods for water treatment and, in particular, to electrochemical systems and methods which are effective in removing one or more target species from a seawater stream.
2. Discussion of Related Art
Systems capable of treating water with an applied electrical field to remove undesirable ionic species therein are known. These electrochemical devices include, but are not limited to, electrodialysis and electrodeionization devices that are conventionally used to generate purified water, such as deionized water.
Within these devices are concentrating and diluting compartments separated by ion-selective membranes. An electrodeionization device conventionally includes alternating electroactive semipermeable anion and cation exchange membranes. Spaces between the membranes are configured to create liquid flow compartments with inlets and outlets. The compartments typically contain adsorption media, such as ion exchange resin, to facilitate ion transfer. An applied electric field imposed via electrodes causes dissolved ions, attracted to their respective counter-electrodes, to migrate through the anion and cation exchange membranes. This generally results in the liquid of the diluting compartment being depleted of ions, and the liquid in the concentrating compartment being enriched with the transferred ions. Typically, the liquid in the diluting compartment is desired (the “product” liquid), while the liquid in the concentrating compartment is discarded (the “reject” liquid).